Electric switch or circuit breaker



April 21, 1925-. 1,534,753

E. A. WATSON ELECTRIC SWITCH 0R CIRCUIT BREAKER Filed July 25, 1922 .4 Inventor:

. Wizzson Patented Apr.- 21, 1925.

UNITED STATES PATENT ()FF-ICE. i

'zeamas'r ANSLEY w'urson', or COVENTRY, ENGLAND, assmnon 'ro THE 0, L. I. MANU- FACTUBING commuw LIMITED, or mnmmem, ENGLAND.

ELECTRIC SWITCH OR CIRCUIT BRKQEER.

.Appltcatlon tiled July'25, 1922. Serial No. 577,451.

Vorks, \Vest Orchard, Coventry, in the county of W arwiek, England, have invented certain new. and useful Improvements Relating to Electric Switches o'r Circuit Breakers,

of which the followinp is a specification.

This invention has for its object to provide an improved electric switch or circuit breaker of the type which is held closed by a permanent'magnet and which automatically opens with reversal of current.' The device is particularly adapted for use in the electric installationsjof motor vehicles, but is applicable to other purposes.

I The invention comprises the combination with a permanent magnet fitted with pole pieces, of a movable switch-operating armature, and a -fixed core with air gap or its equivalent carrying, a winding, the core and armature beint mounted in conjunction with the magnet pole pieces, and the arrangement being such that current in the reverse direction in the winding causes the armature to he released without exerting any demagnetizing action on the magnet.

Referring to the accompanying drawingsz- 'Figure 1 is a diagram illustrating the operation of a switch or circuit breaker constructed in accordance with this invention.

Figures 2, 3, and 4 are respectively side installation of motor vehicles and other like purposes.

In carrying the invention into effect as shown, a pair offlat bars a forming pole pieces and arranged parallel with each other, are connected at one end by a permanent bar magnet b, and at the other by a core c carryswitch contact and adapted to co-oper'ate with a. fixed contact g. The armature is attached to one of the pole pieces by means of a hinge or flexible support, such as a flexible blade, plate or other spring h. Thespring tends to move the armature: away from the pole piece and open the switch. hen the armature is pressed into contact with both pole pieces (thereby closing the switch) it is held by the action of the wig net, the armaturepresenting a path of-lower reluctance -for the magnetic flux than the above mentioned core and air gap. Cur

rent flowing through the winding d after the closing of the switch produces a magnetic flux opposite to that of the magnet but as the armature provides a common path for the two fluxes there is no demagneti'zing effect on the magnet, and the flux due to the current in the winding assists that due to the magnet in holding the switch closed. I

In the event of a reversal of current in thewinding, the flux due to the reversed current is in the same direction as that of themagnct. The flux passing through the arn'iature therefore diminishes, and when a sullicicnt reverse current flows in'the windin; the armature is released and moved by the spring for opening theswiteh. For actuating the armature by hand any convenient provision can be made. For example a linger piece may be attached directly to it),-

or it may be engaged by a slidable finger operated olungersituiited adjacent to the free end of the armature.

A switch or circuit breaker as above described is of very simple construction, and possesses the special property that the current in either direction through the-winding has no den'iagnetizing effect on the permanent magnet.

.Tho inrentiou is not limited to any partic-ular arrangement of the parts provided the operating. conditions are as above described. Also the constructional details may be varied as required. Further t e vention is applicable to a. variety of in which automatic opening of a switch or circuit breaker under prc-determincd conditions is required.

F or the purpose of introducing an automatically varying time element in the opening action of the device,.thc winding d may be shunted by a resistance i made of material having a high temperature coeliicientof resistance. At first the current flowing through i may be relatively large, but as the temperature increases an increasing, proportion of current passes through (Z until the circuit is opened.

Having thus described my invention what .I claim as new and desire to secure by Letters Patent is 1. In electric switches or circuit breakers,

- the combination of a permanent magnet, a

pair of pole pieces. having one pair of ends in conjunction with the magnet,-a magnetizable core in conjunction with the other pair of ends-of the pole pieces and'separapermanent magnet and a current flowing in the winding, "and means for automatically moving the armature away .from the pole pieces and opening the circuit when due to a-r'eversalof current in thewinding the iliilth I armature is sufiiciently diminishddi," siihst intiallxas described.

2. In electric switches or circuit breakers, the combination of a permanent bar magnet, a pair of pole pieces arranged parallel with each other and having one pair of ends in conjunction with the magnet, a magnetizable core in conjunction with the other ends of the pole pieces and separated therefrom by air gaps, a winding on said core, an armature, located across the pole pieces at a position intermediate to the magnet and core, a spring blade serving as a hinge connection between the armature and one of the 'pole pieces and tending to move the armature away from the pole pieces, and a contact member with which the armature e'o-o crates for closing an electric circuit, t

armature after having been pressed on to the pole pieces being held by opposing fluxes produced by the permanent magnet andthe current in the said winding, and released when due to reversal of current the fluxthrongh the armature is sutiiciently-diminished, substantially as described.

In testin'iony whereof I have signed my name to this specification.

ERNEST ANSLEY Wa'rsoN. 

